<h2 mat-dialog-title>Enter income value:</h2>
<p class="error" *ngIf="shouldShowError">{{error}}</p>
<mat-dialog-content>
  <mat-form-field>
    <input matInput placeholder="Value" [(ngModel)]="income" required>
  </mat-form-field>
</mat-dialog-content>
<mat-dialog-actions>
  <button mat-button (click)="cancel()">Cancel</button>
  <button mat-button (click)="submit()" [disabled]="!isFormValid()">Add</button>
</mat-dialog-actions>
